Centrifugal spinning device

ABSTRACT

A centrifugal spinning device having a feed roller and a presser to feed sliver into a fiber liberating device including an opening roller therein, a spinning rotor for depositing liberated fibers supplied from the fiber liberating device within a cavity therein, and a guide tube installed on the axis of rotation of the rotor for guiding out twisted yarn from the rotor, provided with the improvement wherein the entrance opening of the guide tube is formed by ceramic or ceramic composite material, thereby to obtain good spinning stability.

D United States Patent [151 3,696,604 Nozaki et al. [451 Oct. 10, 1972 [54] CENTRIFUGAL SPINNING DEVICE [56] References Cited [72] Il'lVCl'ltOISZ qhflji Nozalri, Kiichi KOIID, :I'OSI'II- UNITED STATES PATENTS klko Sakai, Osami Kamigaito, a" ofNagoya Japan 3,584,451 6/1971 Chrtek et a1 ..57/58.95 3,481,129 12/1969 Shepherd et al......57/58.95 X 3,440,812 4/1969 Stary et a1 ..57/58.95 [73] Assign: f zfifi g ig f irf Ken- Primary ExaminerDonald E. Watkins y g y p Attomey-Berman, Davidson and Herman [22] Filed: May 11, 1971 211 Appl. No.: 142,142 [57] ABSTRACT A centrifugal spinning device having a feed roller and a presser to feed sliver into a fiber liberating device in- [30] Foreign Application Priority Data eluding an opening roller therein, a spinning rotor for May 12, 1970 Japan ..45/46323 depositing liberated fibers supplied from the fiber liberating device within a cavity therein, and a guide 52 us. Cl. ..s7/ss.9s tube installed on the axis of rotation of the rotor for 51] 1m. (:1. ..D01h 1/12, DOlh 7/00 guiding out twisted y from the rotor. provided with 5 the improvement wherein the entrance opening of the Field of Search ..57/58.9 l-58.95

' guide tube is formed by ceramic or ceramic composite material, thereby to obtain good spinning stability.

11 Claims, 6 Drawing Figures CENTRIFUGAL SPINNING DEVICE The present, invention relates to a centrifugal spinning device, and more particularly to an improve ment of the guide tube of the centrifugal spinning device.

In a centrifugal spinning device of conventional type, fibers liberated by a suitable fiber liberating device are fed into a spinning rotor with a cavity rotating at high speed. The fibers are deposited tightly on the inner wall of maximum diameter within the rotor where they are connected to seed yarn to be delivered out through a guide tube installed on the rotation axis of the rotor. The rotation of the rotor twists the fibers taken out of the bundle of deposited fibers. Attempts have been made to provide a durable guide tube for better spinning stability and with less end-downs of yarn. A navel made of carbon steel has been installed at the entrance opening of the guide tube to lessen end-downs of yarn, but sufficient spinning stability has not always been obtained.

An object of the present invention is, therefore, to provide a centrifugal spinning device with good spinning stability.

- Another object of. the present invention is to provide a centrifugal spinning device with which frequency of end-downs of yarn is greatly-lowered for good spinning stability.

Still another object of the present invention is to provide a centrifugal spinning device, having the abovementioned characteristics, wherein the navel on the entrance of the guide tube has a higher static frictional coefficient resulting in less minimum twists per inch necessary for spinning to realize a spinning operation with good quality spinning stability.

A further object of the present invention is to provide a centrifugal spinning device, having the abovementioned characteristics, wherein the navel is made of ceramic or ceramic composite, thereby to achieve the features of good durability and low production cost.

The above-described and other objects and features of the present invention will become more clear from the following detailed description of a preferred embodiment, especially when read in conjunction with the accompanying drawing, in which:

FIG..1 shows a diagrammatic vertical section of a preferred embodiment of the invention;

FIG. 2 is a fragmentary diagrammatic sectional and enlarged view of the guide tube with neighboring parts of the device shown in FIG. 1;

FIG. 3 is a diagrammatic plan view illustrating an extraordinary state of twisting action within the spinning rotor;

FIG. 4 is a graph indicating the relation between twist multipliers of yarn and average duration time between piecing and end-downs;

FIG. 5 is a graph indicating the relation between average number of fibers in a cross-section of yarn and minimum twists per inch necessary for spinning yarn;

FIG. 6 is a graph comparing different materials for making the navel with respect to their relative static frictional coefficient and minimum twists per inch necessary for spinning.

Now referring more particularly to the drawings, FIG. 1 shows a centrifugal spinning device which comprises a feed roller 1 and a presser 2 cooperating to feed sliver 3 into a fiber liberating device 4. An opening roller 5 rotating within the fiber liberating device 4 combs the silver 3 into liberated fibers 6. The liberated fibers 6 are delivered through a feed channel 7 into a spinning rotor 8 which rotates at high speed, for example at 30,000 rpm. The vortex created by the high speed of the rotor 8 and the high centrifugal force applied to the liberated fibers deposits the fibers 6 tightly on the inside surface of wall 9 at its portion of maximum diameter to form a bundle 10.

In spinning or piecing yarn, a seed yarn is inserted into the spinning rotor 8 through the guide tube 12. The seed yarn is connected to a portion of the bundle l0 and delivered out of the tube 12 as yarn l 1 at a lower speed than the circumferential speed of the inner wall 9 of the spinning rotor 8, the delivery speed of yarn 11 being, for instance 30 m/min. This gives the bundle 10 a twist per rotation of the spinning rotor 8 to form yarn 11. In the mentioned instance with a 30,000 r.p.m. rotation of the spinning rotor 8 and the delivery speed of yarn at 30 m/min, the yarn 11 has a twist every 1 mm thereon, that is, the yarn l 1 has 25.4 twists per inch.

As shown more in detail in 'FIG. 2, the centrifugal spinning device comprises the guide tube 12 disposed coaxial with the rotation axis of the spinning rotor 8. A navel 13 with a smooth guiding face 13a is provided at the entrance opening of the guide tube 12 to produce smooth contact between the guide tube 12 and the bundle of fibers 10 to be twisted. A disc separater 14 is installed on the guide tube 12, so that the liberated fibers 6 delivered into the spinning rotor 8 are prevented from touching the bundle of fibers 10 while under twisting action to make the yarn 11.

To avoid end-downs of the bundle of fibers 10, the guiding face 13a of the navel 13 is required to be as smooth as possible. For obtaining a smooth guiding face, buff-polished navels made of carbon steel are generally provided. Thebuff-polished carbon steel navels realize some good spinning stability in spinning out cotton yarn of a specific yarn number of 20s Ne in English Cotton Count. However, when thicker fibers are used, or thinner yarn than 20s Ne is to be spun from fibers of regular thickness, the carbon steel navels have an undesirable tendency to increase end-downs of yarn and to lower the minimum twists per inch necessary for spinning. Thus, the spinning operation has poor stability.

In spinning out yarn of a specific yarn number from fibers of a specific thickness, increase of the delivery speed of the yarn, with the spinning rotor 8 maintained at a certain rotational speed, decreases the twist multiplier of the yarn and shortens the average duration time between piecing and end-downs of yarn, see for instance, FIG. 4 diagramming this relation for 30s Ne yarn spun out of fibers of polyester 3 denier. When a twist number under which yarn is spun out for seconds with no end-down is determined for a minimum of twists per inch necessary for spinning, the minimum twist increases in correspondence to the decrease of the average number of fibers in a cross-section of yarn to lower the spinning stability, (see FIG. 5).

The end-downs of yarn are also caused by entangled fibers and impurities existing within the bundle of fibers 10 between the inner wall 9 of the spinning rotor 8 and the navel 13, and/or by branched fibers 15 as illustrated in FIG. 3. In these cases, the twisting action of the bundle of fibers caused by the spinning rotor 8 is not limited to that within the space between the inner wall 9 and the navel l3. Unnecessary additional twisting action takes place within the guide tube over the navel 13, and the end-downs of yarn increases especially when the average number of fibers of the bundle of fibers 10 becomes small, which, in turn, increases the minimum twists per inch necessary for spinning.

The fundamental concept of the present invention is based on analysis of the relation between the static frictional coefficient of the material of navel 13 and the minimum twists per inch necessary for spinning. In the present invention, a ceramic or ceramic composite is utilized as the material of the navel 13, the ceramic or the ceramic composite material being selected as having the most appropriate static frictional coefficient and good durability, whereby good spinning stability with less end-downs of yarn is obtained in spinning out yarn within a certain limited variety of thickness from fibers within a certain limited variety of thickness.

In FIG. 6, there is shown the relation between the static frictional coefficient (plotted as abscissa ,u.) and minimum twists per inch necessary for spinning (plotted as ordinate 'r), of the navel 13 in spinning yarn of 205 Ne, s Ne or s Ne out of fibers of polyester 3 denier. Resulting curves for these yarns each include points measured for navels 13 made of different materials such as polyforrnaldehyde, polycarbonate, carbon steel, ceramic I-I, epoxy resin, ceramic L, and the like.

It should be observed in FIG. 6 that when the static frictional coefficient is higher, the minimum twists per inch necessary for spinning becomes lower, which renders better spinning stability. Measured values of the static frictional coefficient differ under different conditions, and the numerical test results depicted in FIG. 6 were obtained by measuring the frictional force of twisted yarn of polyester filament with the outlet tensile force of 300g through the Roder Method. The test results are, therefore, considered to be sufficiently accurate for comparison of the facial static frictional coefficients of the navels of the materials mentioned above.

Ceramic L or H (FIG. 6) are made of lithia-aluminosilicate respectively sintered at l,150 C for 10 hours and at l,260 C for 10 hours. The navels made of these materials show higher static frictional coefficients than those made of carbon steel, the material heretofore in use. This lowers the minimum twists per inch necessary for spinning, lessens end-downs of yarn in spinning 205 Ne, 30s Ne and 35s Ne yarns and increases the spinning stability. Ceramic materials also have the desirable characteristic that their static frictional coefficient and wear-resistance can be controlled easily by control of the sintering temperatures. Although epoxy resin shows good spinning stability, as indicated in FIG. 6, its wearresistance is very poor, so that this material is not recommended for practical use.

Experiments indicate that a sintered body made of a ceramic powder mixed with a metallic material such as chromium or the like, is suitable for making the navels. This material is particularly practical for obtaining good spinning stability when static electricity is produced in operation.

In the above described preferred embodiment, the

navel is added to and positioned at the entrance openmg of the guide tube, but the entrance opening 1 self can be made of a ceramic, or ceramic composite, material in a preferred shape.

Thus, it will be clear that variations of the details of construction which are illustrated and described may be resorted to without departing from the true spirit and scope of the invention as defined in the appended claims.

What we claim is:

1. In a centrifugal spinning device having a feed roller and a presser to feed sliver, a fiber liberating device including an opening roller therein receiving said sliver, a spinning rotor for depositing liberated fibers supplied from said fiber liberating device within a cavity in the rotor, and a guide tube coaxial with said rotor for receiving deposited liberated fibers and guiding twisted yarn out of the rotor, the improvement wherein said guide tube has a fiber entrance opening formed of ceramic material.

2. A centrifugal spinning device as set forth in claim 1, wherein said entrance opening of the guide tube is made of lithia-aIumino-silicate sintered substantially at 1,150 C for 10 hours.

3. A centrifugal spinning device as set forth in claim 1, wherein said entrance opening of the guide tube is made of lithia-alumino-silicate sintered substantially at 1,260 C for 10 hours.

4. A centrifugal spinning device as set forth in claim 1, wherein said entrance opening of the guide tube is made of a ceramic composite including a metallic material.

5. A centrifugal spinning device as set forth in claim 4, wherein said metallic material contains chromium.

6. A centrifugal spinning device as set forth in claim 1, wherein said entrance opening of the guide tube is formed as a separate navel made of ceramic material.

7. A centrifugal spinning device as set forth in claim 6, wherein said navel is made of lithia-alumino-silicate sintered essentially at 1,150 C for 10 hours.

8. A centrifugal spinning device as set forth in claim 6, wherein said navel is made of lithia-alumino-silicate sintered essentially at l,260 C for 10 hours.

9. A centrifugal spinning device as set forth in claim 6, wherein said navel is made of a ceramic composite including a metallic material.

10. A centrifugal spinning device as set forth in claim 9, wherein said metallic material contains chromium.

1 1. A centrifugal spinning device as set forth in claim 6, wherein said guide tube is made of metal. 

1. In a centrifugal spinning device having a feed roller and a presser to feed sliver, a fiber liberating device including an opening roller therein receiving said sliver, a spinning rotor for depositing liberated fibers supplied from said fiber liberating device within a cavity in the rotor, and a guide tube coaxial with said rotor for receiving deposited liberated fibers and guiding twisted yarn out of the rotor, the improvement wherein said guide tube has a fiber entrance opening formed of ceramic material.
 2. A centrifugal spinning device as set forth in claim 1, wherein said entrance opening of the guide tube is made of lithia-alumino-silicate sintered substantially at 1,150* C for 10 hours.
 3. A centrifugal spinning device as set forth in claim 1, wherein said entrance opening of the guide tube is made of lithia-alumino-silicate sintered substantially at 1,260* C for 10 hours.
 4. A centrifugal spinning device as set forth in claim 1, wherein said entrance opening of the guide tube is made of a ceramic composite including a metallic material.
 5. A centrifugal spinning device as set forth in claim 4, wherein said metallic material contains chromium.
 6. A centrifugal spinning device as set forth in claim 1, wherein said entrance opening of the guide tube is formed as a separate navel made of ceramic material.
 7. A centrifugal spinning device as set forth in claim 6, wherein said navel is made of lithia-alumino-silicate sintered essentially at 1,150* C for 10 hours.
 8. A centrifugal spinning device as set forth in claim 6, wherein said navel is made of lithia-alumino-silicate sintered essentially at 1,260* C for 10 hours.
 9. A centrifugal spinning device as set forth in claim 6, wherein said navel is made of a ceramic composite including a metallic material.
 10. A centrifugal spinning device as set forth in claim 9, wherein said metallic material contains chromium.
 11. A centrifugal spinning device as set forth in claim 6, wherein said guide tube is made of metal. 